It is the practice in the metal casting industry to mark or label each casting to identify the casting for quality control purposes and to aid in obtaining an accurate production count. The identification marks generally contain such information as the hour of the day or the shift during which the casting was made. Proper identification requires the mark to be changed periodically in order to be accurate. Although other information may also be included, the present invention concerns itself with a portion of the mark which requires updating for each casting.
A convenient method of displaying information is by a series of reference marks located about the circumference of a circle and an indicator mark located within the circle and pointing to a desired reference mark. An example of this technique is the face of a clock. When a foundry desires to indicate the hour during which a casting was made, this information is displayed on the surface of the casting as a series of reference marks located in equal intervals about the circumference of a circle and serving as the hour marks. A pointer mark located within the circle acts as an hour hand. Thus, the hour hand mark would point to the two-hour mark for castings made between 2 and 3 o'clock. At 3 o'clock the position of the hour hand mark would be changed. In a similar fashion other information such as the day of the week or the shift during which the casting was produced might be displayed.
A preferred method for producing a lasting mark upon the surface of a casting is to incorporate a marker or series of markers in a pattern as part of its mold-forming surface. As the pattern is employed to form the green sand or other suitable material into the mold, the image of the markers is impressed into the mold surface. The mark is then cast as part of the surface of the metal.
Typically, changing or updating the mark is difficult. Using one method, an operator is required to enter a molding machine in order to reach the pattern surface and manually change the marker. This procedure is not only time consuming, but requires elaborate safety precautions to protect the operator while inside the machine. However, development of a numbering or marking device allowing the operator to change the mark from outside the molding machine has been hampered because of the durable construction necessary to withstand the tremendous jolts and pressure of the mold-forming operations.
It would be desirable to produce a numbering device which facilitates a changing of a mark as desired and maximizes production efficiency.